To meet the demand for wireless data traffic having increased since deployment of 4G (4th-Generation) communication systems, efforts have been made to develop an improved 5G (5th-Generation) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘beyond 4G network’ or a ‘post LTE system’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation and the like.
In the 5G system, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
5G is not a single kind of wireless technique but is a combination of existing wireless communications techniques. At present, the peak rate of LTE may reach 100 Mbps, whereas the peak rate of 5G may reach 10 Gbps, increased by 100 times. The 4G networks have limited spontaneous processing abilities and cannot support some services such as high definition video, high quality voice, augmented reality and virtual reality, etc. 5G will introduce more advanced technologies to meet the increasing requirement of mobile services through higher spectrum efficiency, more spectrum resources and cells with higher density, so as to solve the problems of 4G and build a network with high transmission rate, high capacity, low latency, high reliability and better user experiences. The 5G architecture includes a 5G access network and a 5G core network. User equipment (UE) communicates with a data network through the access network and the core network.